OXNAS: reimplement timer
Revert "OXNAS: fix various time issues because use a non-standard HZ rate"

This reverts commit 2bb8e2a56c941616c1d4da72d90d94f3801c9eae.
OXNAS: revert change related to CONFIG_SYS_HZ
Revert "OXNAS: another fix for non-standard tick rate"

This reverts commit 166d6096baea87057187f17492698400589c175e.
OXNAS: use PLLB as usb reference clk, make it not depend on sata phy

Though rom seems initialize sata phy anyway.